Thermo circuit-closer for electric fire-alarms



No. 463,298. Patented Nov. 17,1891.

I (No Model.)

J. WRIGLEY & G. P. CHAMBERS. THERMO CIRCUIT CLOSER FOR ELECTRIC FIRE ALARMS.

UNITED STATES PATENT OFFICE.

JOHN VRIGLEY AND GEORGE I. CHAMBERS, OF PATTERSON, NE\V JERSEY.

THERMO CIRCUIT-CLOSER FOR ELECTRIC FIRE-ALARMS.

SPECIFICATION forming part of Letters Patent No. 463,298, dated November 17, 1891.

Application filed June 26, 1891- Serial No. 397,587- (No modehl To aZZ whom it may concern:

Be it known that we, JOHN \VRIGLEY and GEORGE P. CHAMBERS, both of Paterson, in the county of Passaic and State of New Jersey, have invented a new and useful Improvement in Thernio Circuit-Closers for Electric Fire-Alarms, of which the following is a specification.

Our invention relates to circuit-closers for .10 electric fire-alarms, in which the heat from a tire in proximity thereto ignites an explosive and by bursting the bulb in which it is contained releases a spring actuated contactpiece and closes circuit, the object being to automatically ring" a fire-alarm in case of a fire occurring any where near.

WVe will now proceed to describe our in vention with reference to the accompanying drawing', and then point out its novel features in 2 claims.

'With reference to the accompanying drawing, A represents a suitable base, preferably of some non-conducting" material-such, for i stance, as woodto which is attached a hole low metallic socket B. The socket is here shown as attached thereto by means of screws passing through lugs 12 at the sides thereof, one of said screws, as Z), forming a terminal for an electric wire in. The base A has a recess at opposite the point at which the socket is attached and within the recess is a contactpiece a, a binding-screw a connecting the same with the other electric wire 4:. Now if electrical connection is made between the ter- 5 minal b and the contact-piece a, the circuit will be closed, and the electric bell shown at E, which here constitutes the fire-alarn'i, will be rung. The said connect-ion is made automatically in the following manner: Contained 4o partially within the socket B and adapted to move longitudinally therethrough is a circuit closer D, consisting of a rod provided at one end with a contact-piece b and terminating at its opposite end in a head 61. Surrounding said rod is a coiled compressionspring 1), ex-

tending between the contact-piece b and the bottom I) of the socket l3. Said spring tends at all times to force the circuit-closer toward the contactpiece a, but is normally prevented from doing so by the interposition between the said socket and the head (Z of the said circult-closer of a frangible bulb O. The bulb (I, which will be preferably of glass, is kept filled with some explosivesuch, for instance, as gun-cottonand, as shown ate in the drawing, a small quantity of said explosive is permitted to come without the bulb. Now in case of a fire that portion will become ignited instantly,.exploding that which is contained within the glass bulb, bursting the bulb and releasing the spring-actuated circuit-closer l), which, by the pressure of the spring, will be forced against the contact-piece a, closing circuit and ringing, the fire-alarm.

\Vhat we claim is l. The combination, in a thermo circuitcloser, of a stationary contact-piece,a springactuated movable contactpiece, and a frangible bulb containingau explosive, said contactpieces being normally kept out of contact by said bulb, substantially as specified.

2. The combination, in a thermo circuitcloser, of a fixed base, a stationary contactpiece attached to said base, a socket attached to said base opposite said contact-piece,a rod working lengthwise in said socket and provided at its inner end with a contact-piece and at its outer end with a head, a frangible bulb containing an explosive interposed between said socket and the head of said rod, and a spring applied to said rod within said socket to press the said rod toward the stationary contact-piece, all substantially as and for the purpose herein set forth.

JOHN WRIGLEY. GEORGE 1". CHAMBERS. \Yitnesses:

FRED. T. GREG-sou, WILLIAM CLAYTON. 

